Apparatus and method for removably mounting filters to a photographic lens

ABSTRACT

A coupling system and method for removably mounting filters to a photographic camera lens. The coupling system includes a lens coupling element and filter coupling element. The lens coupling element has a magnetically attractive projecting ring that is telescopically received by and magnetically coupled within the annular body of the filter coupling element. The forward end of the annular body operably supporting a filter material.

BACKGROUND

The present invention is directed generally to photographic equipmentand more particularly to the attachment of filters or other accessoriesto photographic lenses.

Presently, installing or removing a filter from a photographic lensrequires the manual and tedious threading and unthreading of the filterfrom the lens each time a different filter is desired. This task isespecially inconvenient during the performance or many photographicassignments, and particularly during weddings, sporting events, or whenphotographing wildlife. It is also difficult to perform this task withcold or gloved hands, while otherwise distracted, or when the threads ofthe filter, lens, or both have been damaged.

Hence, the ostensibly routine task of changing a filter often requires afrustrating and inordinate level of concentration to complete. Mostphotographers are familiar with the recurring difficulty and multiplefalse starts that attempting to attach filter to lens can entail. As aresult, many photographers avoid changing filters unless absolutelynecessary, and creative opportunities are thus frequently sacrificed toexpediency.

The method of attaching filters to lenses remains perhaps the onlyfeature of photographic equipment design to persist unmodified forseveral decades. A puzzling oversight, since most photographersappreciate the convenience of, for example, instant bayonet mounts forlens attachment, and quick-release adapters for mounting camera totripod, both of which eliminate the use of threaded devices.

The standard method for attaching filters to lenses typically features afinely threaded female insert or threaded body along the inside frontcircumference of a lens barrel. These threads are present to provide areceptive fixture to accept and temporarily hold male-threaded filtersor other accessories. Such threads are difficult to machine and prone tocross threading or other damage which renders them burdensome to use orultimately, unusable. If necessary, re-machining of these threads isexpensive and, depending on the value and type of lens, usuallyimpractical. Similarly, photographic filters and other accessoriesrequire a correspondingly-threaded male body. Most commonly, filters aremachined from aluminum and receive a black anodized finish. Regularinstallation and removal of the device causes deterioration of the fineanodized threads. This eventually results in the tendency of the filterto bind, particularly when installed into another aluminum fixture, withcross threading damage the usual result. Once damaged, it is notcost-effective to repair a filter, and depending on the extent ofdamage, may render the filter unusable.

Others have attempted to attach filters or accessories to lensesutilizing magnetic attraction. However all these prior attempts wereoffered as additive devices to modify or augment existing methods, andnone presented a viable alternative to the current industry-standardmethod. All are characterized by either impractical utility of thedesign, or unacceptable size and bulk. Some incorporate multiplemagnets, specifically polarized and oriented, adding weight and cost,introducing design and manufacturing complexity, and furthermorenecessitating specifications to identify polarity and installationorientation of the magnets in order to insure proper functionality ofthe devices. Consequently, such prior attempts have not met withcommercial success.

DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 is a perspective view of a typical, conventional camera having alens, which may or may not be removable, and illustrating how aconventional, prior art filter threadably mounts to within the threadedrecess of the lens.

FIG. 2 is an exploded perspective view of one embodiment of a filtercoupler system for removably mounting a filter to a photographic lens.

FIG. 3 is a perspective view of the filter coupler system of FIG. 2shown assembled.

FIG. 4 is a partial cross-sectional view of the filter coupler system asviewed along lines 4-4 of FIG. 3.

FIG. 5 is a partial cross-sectional view of an alternative embodiment ofa filter coupler system for removably mounting a filter to aphotographic lens.

FIG. 6 is a partial cross-sectional view of another alternativeembodiment of a filter coupler system for removably mounting a filter toa photographic lens.

FIG. 7 is a partial cross-sectional view of another alternativeembodiment of a filter coupler system for removably mounting a filter toa photographic lens.

DESCRIPTION

Referring now to the drawings, wherein like reference numerals designateidentical or corresponding parts throughout the several views, FIG. 1 isa perspective view of a typical conventional camera 10 (digital or film)with a lens 12. It should be understood that the camera 10 and lens 12of FIG. 1 are intended to be representative of any camera with aremovable or fixed photographic lens. The term “lens” or “lenses,” asused herein, should be understood as meaning the element or component ofa camera which allows for, and controls, the transmission of light toform an image on film or a digital light collection device. Lenses aretypically manufactured in an array of fixed or varying focal lengths andmount to cameras via proprietary and non-standardized mounts such thatthey are generally not interchangeable between manufacturers.

While the lenses may be proprietary to the camera manufacturers,virtually all lenses include an industry standard and universally usedand recognized threaded recess 14 at the front end 16 of the lens barrel18. This threaded recess 14 is used to threadably receive a filter 20 orother accessory, allowing for interchangeability of accessories of anyappropriately sized device on any lens produced by any manufacturer. Thethreaded recesses 14 are normally defined by size in millimeters, e.g.,62 mm, 77 mm, etc.

As used herein, the term “filter” or “filters” should be understood asmeaning any optically translucent material which, when placed in frontof the lens, alters the incoming light to achieve a desired modificationof the resulting image. Filters are used almost universally byprofessional and amateur photographers alike. Good equipment maintenancepractices dictate that a photographic filter be kept on a lens at alltimes to protect the delicate front element from damage. Typical filtersremove UV radiation, alter image contrast, and balance or improve colorrendition and saturation. Specialty filters may be used creatively toadd diffusion, create patterns or introduce unusual color effects. Atypical filter 20 is comprised of a desired filter material 22 mountedwithin a filter body 24 having an exterior threaded flange 26 sized tobe threadably received within the threaded recess 14 of the lens 12.Filters 20 are produced in standard sizes corresponding to the lensconfigurations, thus allowing interchangeability between identicallysized filters and accessories from any manufacturer on any lens.

Referring now to FIG. 2, an exploded perspective view of one embodimentof the filter coupler system 100 is illustrated. FIG. 3 is a perspectiveview of the filter coupler system of FIG. 2 shown assembled. As bestillustrated in FIG. 3, the filter coupler system 100 has a rearward end102 adjacent the camera lens 12 and a forward end 104 adjacent theconventional filter 20. FIG. 4 is an enlarged partial cross-sectionalview as viewed along lines 4-4 of FIG. 3.

The filter coupler 100 preferably comprises two components; a lenscoupling element 110 and a filter coupling element 112. The lenscoupling element 110 preferably includes an annular body 114 having aforward end 116 and a rearwardly extending annular flange 118 havingexterior threads 120 sized to be received within the female threadedrecess 14 of the lens 12. The forward end 116 of the annular body 114 ofthe lens coupling element 110 preferably includes a front face 122 (FIG.4) having an inside diameter that does not obstruct the lens 12. Achannel 124 (FIG. 4) is preferably formed within the front face toreceive an insert 126, preferably made of steel or other ferromagneticor magnetically attractive material.

The insert 126 may be press fit and/or glued, bonded or otherwise fixedwithin the channel 124. In the preferred embodiment, the insert 126projects a short distance beyond the front face 122 of the lens couplingelement 110 and has an outside diameter slightly less than the insidediameter of the rearward end of the filter coupling element 112(discussed later). Additionally, the outer circumferential edge of theinsert 126 is preferably machined with a small chamfer 128 (FIG. 4), thepurpose of which will be discussed later. The insert 126 may bechemically plated, coated or encapsulated, or otherwise manufactured toprovide a cosmetically attractive and durable surface. The channel 124and the insert 126 are preferably annular, but the channel 124 andinsert 126 may comprise a series of segments spaced circumferentiallyaround the front face 122.

The outer circumference of the lens coupling element 110 may includefins or other raised portions at regular intervals to differentiate thelens coupling element 110 from the lens 12 and other elements of thefilter coupler assembly 100 so as to enable a user to more easily gripthe lens coupling element for installation and removal.

Continuing to refer to FIGS. 2 and 4, the filter coupling element 112preferably comprises an annular body 130 having a forward end 132 and arearward end 134. The forward end preferably includes interior threads136 to threadably receive the male exterior threaded flange 26 of astandard filter 20. When viewed in cross-section (FIG. 4), the annularbody 130 of the filter coupling element 112 is preferably T-shaped withan inwardly projecting rib 138. The inside diameter of the rib 138 ispreferably the same as the inside diameter of the front face 122 of thelens coupling element 110. A thin magnet 140 is preferably fixed to therearward face of the rib 138 such that it is in coaxial alignment withthe magnetically attractive insert 126 of the lens coupling element 110.The magnet 140 preferably has an outside diameter slightly less than theoutside diameter of the rib 138, and an inside diameter that is the sameas or slightly greater than the inside diameter of the rib 138, so asnot to obstruct the lens 12 or interfere with the transmission of light.It should be appreciated that although the magnet 140 is preferably inthe shape of a thin ring, the magnet 140 may also comprise a series ofsegments spaced circumferentially around the rearward face of the rib138 positioned to magnetically attract the insert 126.

Referring to FIG. 4, it is preferred that the thickness of the magnet140 and the axial position of the rib 138 within the annular body 130 towhich it is affixed, is such that the magnet 140 comes in close ordirect contact with the mounting surface of the projecting insert 126forwardly of the rearward end of the filter coupling element 112,thereby providing a telescoping connection having lateral stability andwhich prevents inadvertent misalignment or movement of the coupler 100while in use.

It is preferred that only the forwardly projecting insert 126 ismagnetically attractive, and not any other part of the front face 122 orbody 114 of the lens coupling element 110. This serves to isolate theattraction of the magnet 140 to the projecting insert 126 in order toaffect proper seating of the filter coupling element 112 onto the lenscoupling element 110 and prevent the undesirable misalignment that straymagnetic attraction might induce. Accordingly, the bodies 114, 130 ofthe lens coupling element 110 and the filter coupling element 112 arepreferably fabricated from aluminum, plastic, or other suitably rigid,non-ferromagnetic material.

In practice, a single lens coupling element 110 may remain threadablymounted to the camera lens 12 as shown and, ideally, a plurality offilter coupling elements 112 will have already been threaded onto thevarious different filters 20 that the photographer may utilize. Thus,when the photographer desires to switch to a different filter 20, thephotographer can simply pull on the filter coupling element 112 toremove it from the magnetically coupled lens coupling element 110. Thephotographer can then simply reach for a different desired filter 20already having a filter coupling element 112 threadably attachedthereto, thereby allowing the photographer to quickly substitute onefilter 20 for another. The telescoping, self aligning connection betweenthe two elements 110, 112 which is guided by the chamfered outercircumferential edge 128 and magnetic attraction between the twoelements 110, 112 preferably provides the photographer with an audible“clap” and positive feel so he or she knows that the two elements 110,112 are properly seated without necessarily having to double check theconnection.

FIG. 5 illustrates a second alternative embodiment of a filter coupler200. As in the first embodiment, in this second embodiment, the filtercoupler 200 also comprises a lens coupling element 210 magneticallycoupled to a filter coupling element 212. The lens coupling element 210is substantially identical to the lens coupling element 110 previouslydescribed in the first embodiment. The lens coupling element 210preferably includes an annular body 214 having a forward end 216 and arearwardly extending annular flange 218 having exterior threads 220sized to be received within the female threaded recess 14 of the lens12. The forward end 216 of the annular body 214 of the lens couplingelement 210 preferably includes a front face 222 having an insidediameter that does not obstruct the lens 12. A channel 224 is preferablyformed within the front face to receive an insert 226, preferably madeof steel or other ferromagnetic or magnetically attractive material.

The insert 226 may be press fit and/or glued, bonded or otherwise fixedwithin the annular channel 224. As in the previous embodiment, theinsert 226 projects a short distance beyond the front face 222 of thelens coupling element 210 and has an outside diameter slightly less thanthe inside diameter of the rearward end of the filter coupling element212. As in the previous embodiment, the outer circumferential edge ofthe insert 226 is preferably machined with a small chamfer 228. Theinsert 226 may be chemically plated, coated or encapsulated, orotherwise manufactured to provide a cosmetically attractive and durablesurface. The channel 224 and the insert 226 are preferably annular, butthe channel 224 and insert 226 may comprise a series of segments spacedcircumferentially around the front face 222.

The outer circumference of the lens coupling element 210 may includefins or other raised portions at regular intervals to differentiate thelens coupling element 210 from the lens 12 and other elements of thefilter coupler assembly 200 so as to enable a user to more easily gripthe lens coupling element for installation and removal.

The filter coupling element 212 preferably comprises an annular body 230having a forward end 232 and a rearward end 234. However, unlike theprevious embodiment, the forward end does not include interior threadsto threadably receive the male exterior threaded flange 26 of a standardfilter 20. Instead, as described later, in this second embodiment, thefilter material 22 is disposed within the filter coupling element 212thereby eliminating the need for a attaching a separate filter 20. As inthe first embodiment, when viewed in cross-section, the annular body 230of the filter coupling element 212 is preferably T-shaped with aninwardly projecting rib 238. The inside diameter of the rib 238 ispreferably the same as the inside diameter of the front face 222 of thelens coupling element 210. A thin magnet 240 is preferably fixed to therearward face of the rib 238 such that it is in coaxial alignment withthe magnetically attractive insert 226 of the lens coupling element 210.The magnet 240 preferably has an outside diameter slightly less than theoutside diameter of the rib 238 and an inside diameter that is the sameas or slightly greater than the inside diameter of the rib 238 so as notto obstruct the lens 12 or interfere with the transmission of light. Itshould be appreciated that although the magnet 240 is preferably in theshape of a thin ring, the magnet 240 may also comprise a series ofsegments spaced circumferentially around the rearward face of the rib238 positioned to magnetically attract the insert 226.

As illustrated in FIG. 5, it is preferred that the thickness of themagnet 240 and the axial position of the rib 238 within the annular body230 to which it is affixed is such that the magnet 240 comes in close ordirect contact with the mounting surface of the projecting insert 226forwardly of the rearward end of the filter coupling element 212,thereby providing a telescoping connection having lateral stability andwhich prevents inadvertent misalignment or movement of the coupler 200while in use.

As in the first embodiment, it is preferred that only the forwardlyprojecting insert 226 is magnetically attractive, and not any other partof the front face 222 or body 214 of the lens coupling element 210. Thisserves to isolate the attraction of the magnet 240 to the projectinginsert 226 in order to affect proper seating of the filter couplingelement 212 onto the lens coupling element 210 and prevent theundesirable misalignment that stray magnetic attraction might induce.Accordingly, the bodies 214, 230 of the lens coupling element 210 andthe filter coupling element 212 are preferably fabricated from aluminum,plastic, or other suitably rigid, non-ferromagnetic material.

In practice, a single lens coupling element 210 may remain threadablymounted to the camera lens 12 as shown and, ideally, a plurality offilter coupling elements 212 are provided with various filter materials22 disposed therein. Thus, when the photographer desires to switch to adifferent filter material for a different affect, the photographer cansimply pull on the filter coupling element 212 to remove it from themagnetically coupled lens coupling element 210. The photographer canthen simply reach for a different filter coupling element 210 with thedesired filter material 22, thereby allowing the photographer to quicklysubstitute between filter materials. The telescoping, self aligningconnection between the two elements 210, 212 which is guided by thechamfered outer circumferential edge 228 and magnetic attraction betweenthe two elements 210, 212 preferably provides the photographer with anaudible “clap” and positive feel so he or she knows that the twoelements 210, 212 are properly seated without necessarily having todouble check the connection.

FIG. 6 illustrates a third alternative embodiment of a filter coupler300. As in the previous embodiments, in this third embodiment, thefilter coupler 300 also comprises a lens coupling element 310magnetically coupled to a filter coupling element 312. Unlike the firsttwo embodiments, however, in the third embodiment, the lens couplingelement 310 is affixed to, or is otherwise a part of, or is integralwith the lens 12′ produced by an original equipment manufacturer (OEM).In this embodiment, the lens 12′ includes a front face 322 within whichis a channel 324 that receives an insert 326, preferably made of steelor other ferromagnetic or magnetically attractive material.

The insert 326 may be press fit and/or glued, bonded or otherwise fixedwithin the channel 324. As in the previous embodiments, the insert 326projects a short distance beyond the front face 322 of the lens and hasan outside diameter slightly less than the inside diameter of therearward end of the filter coupling element 312. As in the previousembodiments, the outer circumferential edge of the insert 326 ispreferably machined with a small chamfer 328. The insert 326 may bechemically plated, coated or encapsulated, or otherwise manufactured toprovide a cosmetically attractive and durable surface. The channel 324and the insert 326 are preferably annular, but the channel 324 andinsert 326 may comprise a series of segments spaced circumferentiallyaround the front face 322.

The filter coupling element 312 preferably comprises an annular body 330having a forward end 332 and a rearward end 334. The forward endpreferably includes interior threads 336 to threadably receive the maleexterior threaded flange 26 of a standard filter 20. When viewed incross-section, the annular body 330 of the filter coupling element 312is preferably T-shaped with an inwardly projecting rib 338. The insidediameter of the rib 338 is preferably the same as the inside diameter ofthe front face 322 of the lens coupling element 310. A thin magnet 340is preferably fixed to the rearward face of the rib 338 such that it isin coaxial alignment with the magnetically attractive insert 326 of thelens coupling element 310. The magnet 340 preferably has an outsidediameter slightly less than the outside diameter of the rib 338 and aninside diameter that is the same as or slightly greater than the insidediameter of the rib 338 so as not to obstruct the lens 12′ or interferewith the transmission of light. It should be appreciated that althoughthe magnet 340 is preferably in the shape of a thin ring, the magnet 340may also comprise a series of segments spaced circumferentially aroundthe rearward face of the rib 338 positioned to magnetically attract theinsert 326.

As illustrated in FIG. 6, it is preferred that the thickness of themagnet 340 and the axial position of the rib 338 within the annular body330 to which it is affixed is such that the magnet 340 comes in close ordirect contact with the mounting surface of the projecting insert 326forwardly of the rearward end of the filter coupling element 312,thereby providing a telescoping connection having lateral stability andwhich prevents inadvertent misalignment or movement of the coupler 300while in use.

It is preferred that only the forwardly projecting insert 326 ismagnetically attractive, and not any other part of the front face 322 orlens 12′. This serves to isolate the attraction of the magnet 340 to theprojecting insert 326 in order to affect proper seating of the filtercoupling element 312 onto the lens coupling element 310 and prevent theundesirable misalignment that stray magnetic attraction might induce.Accordingly, the lens 12′ and the filter coupling element 312 arepreferably fabricated from aluminum, plastic, or other suitably rigid,non-ferromagnetic material.

In practice, a single lens coupling element 310 remains fixed to thecamera lens 12′ as shown and, ideally, a plurality of filter couplingelements 312 will have already been threaded onto the various differentconventional filters 20 that the photographer may utilize. Thus, whenthe photographer desires to switch to a different filter 20, thephotographer can simply pull on the filter coupling element 312 toremove it from the magnetically coupled lens coupling element 310. Thephotographer can then simply reach for a different desired filter 20already having a filter coupling element 312 threadably attachedthereto, thereby allowing the photographer to quickly substitute onefilter 20 for another. The telescoping, self aligning connection betweenthe two elements 310, 312 which is guided by the chamfered outercircumferential edge 328 and magnetic attraction between the twoelements 310, 312 preferably provides the photographer with an audible“clap” and positive feel so he or she knows that the two elements 310,312 are properly seated without necessarily having to double check theconnection.

FIG. 7 illustrates a fourth alternative embodiment of a filter coupler400. As in the previous embodiments, in this fourth embodiment, thefilter coupler 400 also comprises a lens coupling element 410magnetically coupled to a filter coupling element 412. Like the thirdembodiment, in this fourth embodiment, the lens coupling element 410 isaffixed to, or is otherwise a part of, or is integral with the lens 12″produced by an original equipment manufacturer (OEM). In thisembodiment, the lens 12″ includes a front face 422 within which is achannel 424 that receives an insert 426, preferably made of steel orother ferromagnetic or magnetically attractive material.

The insert 426 may be press fit and/or glued, bonded or otherwise fixedwithin the channel 424. As in the previous embodiments, the insert 426projects a short distance beyond the front face 422 of the lens and hasan outside diameter slightly less than the inside diameter of therearward end of the filter coupling element 412. As in the previousembodiment, the outer circumferential edge of the insert 426 ispreferably machined with a small chamfer 428. The insert 426 may bechemically plated, coated or encapsulated, or otherwise manufactured toprovide a cosmetically attractive and durable surface. The channel 424and the insert 426 are preferably annular, but the channel 424 andinsert 426 may comprise a series of segments spaced circumferentiallyaround the front face 422.

The filter coupling element 412 preferably comprises an annular body 430having a forward end 432 and a rearward end 434. As in the secondembodiment, the forward end does not include interior threads tothreadably receive the male exterior threaded flange 26 of a standardfilter 20. Instead, in this fourth embodiment, the filter material 22 isdisposed within the filter coupling element 412 thereby eliminating theneed for a attaching a separate filter coupling element 20. As in theprevious embodiments, when viewed in cross-section, the annular body 430of the filter coupling element 412 is preferably T-shaped with aninwardly projecting rib 438. The inside diameter of the rib 438 ispreferably the same as the inside diameter of the front face 422 of thelens coupling element 410. A thin magnet 440 is preferably fixed to therearward face of the rib 438 such that it is in coaxial alignment withthe magnetically attractive insert 426 of the lens coupling element 410.The magnet 440 preferably has an outside diameter slightly less than theoutside diameter of the rib 438 and an inside diameter that is the sameas or slightly greater than the inside diameter of the rib 438 so as notto obstruct the lens 12″ or interfere with the transmission of light. Itshould be appreciated that although the magnet 440 is preferably in theshape of a thin ring, the magnet 440 may also comprise a series ofsegments spaced circumferentially around the rearward face of the rib438 positioned to magnetically attract the insert 426.

As illustrated in FIG. 7, it is preferred that the thickness of themagnet 440 and the axial position of the rib 438 within the annular body430 to which it is affixed is such that the magnet 440 comes in close ordirect contact with the mounting surface of the projecting insert 426forwardly of the rearward end of the filter coupling element 412,thereby providing a telescoping connection having lateral stability andwhich prevents inadvertent misalignment or movement of the coupler 400while in use.

As in the previous embodiments, it is preferred that only the forwardlyprojecting insert 426 is magnetically attractive, and not any other partof the front face 422 or lens 12″. This serves to isolate the attractionof the magnet 440 to the projecting insert 426 in order to affect properseating of the filter coupling element 412 onto the lens couplingelement 410 and prevent the undesirable misalignment that stray magneticattraction might induce. Accordingly, the lens 12″ and the filtercoupling element 412 are preferably fabricated from aluminum, plastic,or other suitably rigid, non-ferromagnetic material.

In practice, a single lens coupling element 410 remains fixed to thecamera lens 12″ as shown and, ideally, a plurality of filter couplingelements 412 are provided with various filter materials 22 disposedtherein. Thus, when the photographer desires to switch to a differentfilter material for a different affect, the photographer can simply pullon the filter coupling element 412 to remove it from the magneticallycoupled lens coupling element 410. The photographer can then simplyreach for a different filter coupling element with the desired filtermaterial 22, thereby allowing the photographer to quickly substitutebetween filter materials. The telescoping, self aligning connectionbetween the two elements 410, 412 which is guided by the chamfered outercircumferential edge 428 and magnetic attraction between the twoelements 410, 412 preferably provides the photographer with an audible“clap” and positive feel so he or she knows that the two elements 410,412 are properly seated without necessarily having to double check theconnection.

In each of the embodiments, the magnet may be produced from anyappropriate permanently magnetizable material which provides properfunctionality, reliability, and durability, and of which can befabricated to the necessary form and desired tolerances. Thepolarization of the magnet may be either through the thickness or acrossthe diameter, whichever is easiest and most cost-effective to produce.The polarity does not need to be known or indicated when the magnet isinstalled. The magnetic attraction provided by the magnet should besufficient such that when the filter coupling element 112, 212, 312, 412is placed in proximity to the insert 126, 226, 326, 426 of the lenscoupling element 110, 210, 310, 410, the magnetic attraction pulls thefilter coupling element into place and an instantaneous alignment andseating occurs, securely attaching the filter coupling element to thelens coupling element. The magnet preferably has sufficient holdingpower to support the entire weight of the camera, yet preferablyrequires only moderate finger strength sufficient to overcome themagnetic attraction to remove the filter coupling element from the lenscoupling element. The magnet may be chemically or otherwise coated toproduce a cosmetically attractive finish and add durability.

In all embodiments, the focused area of attraction provided by thenarrow mounting surface of the insert 126, 226, 326, 426 and magnetic140, 240, 340, 440 enables the filter coupling element 112, 212, 312,412 to effortlessly seat itself properly, firmly and repeatedly to thelens coupling element 110, 210, 310, 410 without the necessity ofadjustments, regardless of the orientation or angle with which it isoffered for attachment. In each of the embodiments, when the twoelements properly come together, a distinctive clapping sound confirmsthat the filter coupling element is positively seated on the lenscoupling element.

The foregoing description is presented to enable one of ordinary skillin the art to make and use the invention and is provided in the contextof a patent application and its requirements. Various modifications tothe preferred embodiment of the apparatus, and the general principlesand features of the system and methods described herein will be readilyapparent to those of skill in the art. Thus, the present invention isnot to be limited to the embodiments of the apparatus, system andmethods described above and illustrated in the drawing figures, but isto be accorded the widest scope consistent with the spirit and scope ofthe appended claims.

1. A coupling system for removably mounting filters to a photographiclens, comprising: a lens coupling element having a front face disposedforwardly of a lens within a camera lens barrel, said lens couplingelement further having a magnetically attractive projection extendingforwardly of said front face and having an outside diameter less than anoutside diameter of said camera lens barrel; a filter coupling elementhaving an annular body with a rearward end and a forward end, saidrearward end sized to telescopically receive said projection and havinga magnet recessed a distance within said annular body to magneticallycouple with said telescopically received projection, said forward end ofsaid annular body operably supporting a filter material.
 2. The couplingsystem of claim 1 wherein said lens coupling element includes an annularlens coupling body having a rearwardly projecting flange with externalthreads sized to be threadably received within a threaded recess of saidcamera lens barrel.
 3. The coupling system of claim 1 wherein said lenscoupling element is integral with said camera lens barrel.
 4. Thecoupling system of claim 1 wherein said forward end of said filterannular body includes a forwardly projecting flange with internalthreads sized to threadably receive an externally threaded flange of afilter body within which the filter material is disposed.
 5. Thecoupling system of claim 1 wherein said forward end of said filterannular body includes a filter material.
 6. The coupling system of claim3 wherein said forward end of said filter annular body includes aforwardly projecting flange with internal threads sized to threadablyreceive an externally threaded flange of a filter body within which thefilter material is disposed.
 7. The coupling system of claim 3 whereinsaid forward end of said filter annular body includes a filter material.8. The coupling system of claim 1 wherein said magnetic attractiveprojection includes a sloped outer peripheral surface to assist intelescopically aligning said filter coupling element with said lenscoupling element.
 9. For a camera having a lens barrel with a forwardthreaded recess for threadably receiving lens filters, a removablefilter coupling system, comprising: a lens coupling element having arearwardly projecting flange with external threads sized to bethreadably received within the threaded recess of the lens barrel, saidlens coupling element further having a magnetically attractiveprojection that extends forwardly and has an outside diameter less thanan outside diameter of the lens barrel; a filter coupling element havingan annular body with a rearward end and a forward end, said rearward endsized to telescopically receive said projection and having a magnetrecessed a distance within said annular body to magnetically couple withsaid telescopically received projection, said forward end of saidannular body operably supporting a filter material.
 10. The couplingsystem of claim 9 wherein said forward end of said filter annular bodyincludes a forwardly projecting flange with internal threads sized tothreadably receive an externally threaded flange of a filter body withinwhich the filter material is disposed.
 11. The coupling system of claim9 wherein said forward end of said filter annular body includes a filtermaterial.
 12. The coupling system of claim 1 wherein said magneticallyattractive projection includes a sloped outer peripheral surface toassist in telescopically aligning said filter coupling element with saidlens coupling element.
 13. A method of preparing a camera a lens barrelwith a forward threaded recess for threadably receiving lens filters tointerchangeably magnetically receive a plurality of different lensfilters, said method comprising: providing a lens coupling elementhaving a rearwardly projecting flange with external threads, said lenscoupling element further having a magnetically attractive projectionthat extends forwardly and has an outside diameter less than an outsidediameter of the lens barrel; threading said rearwardly projecting flangeof said lens coupling element into the threaded recess of the lensbarrel; providing a first filter coupling element having a first annularbody with a rearward end and a forward end, said rearward end sized totelescopically receive said projection of said lens coupling element andhaving a magnet recessed a distance within said annular body, saidforward end of said first annular body operably supporting a firstfilter material; magnetically coupling said first filter couplingelement onto said lens coupling element with said projection of saidlens coupling element telescopically received within said rearward endof said annular body of said first filter coupling element.
 14. Themethod of claim 13 further comprising: providing a second filtercoupling element having a second annular body with a rearward end and aforward end, said rearward end sized to telescopically receive saidprojection of said lens coupling element and having a magnet recessed adistance within said annular body, said forward end of said secondannular body operably supporting a second filter material different fromsaid first filter material; removing said first magnetically coupledfirst filter coupling element from said lens coupling element;magnetically coupling said second filter coupling element onto said lenscoupling element with said projection of said lens coupling elementtelescopically received within said rearward end of said annular body ofsaid second filter coupling element.
 15. The method of claim 13 whereinsaid forward end of said first filter annular body includes a forwardlyprojecting flange with internal threads sized to threadably receive anexternally threaded flange of a filter body within which the firstfilter material is disposed.
 16. The method of claim 14 wherein saidforward end of said second filter annular body includes a forwardlyprojecting flange with internal threads sized to threadably receive anexternally threaded flange of a filter body within which the secondfilter material is disposed.
 17. The method of claim 14 wherein saidmagnetically attractive projection includes a sloped outer peripheralsurface to assist in telescopically aligning said first and said secondfilter coupling elements with said lens coupling element.